Steering and suspension systems for work vehicles (e.g., tractors, sprayers, etc.) have been developed in some arrangements in the art. Typically a plurality of wheels are provided which can turn in two-wheel steering, four-wheel steering, or crab steering configurations. However, the wheels of such systems have a limited range of movement--typically about ninety degrees. Some work vehicle maneuvers require greater steering flexibility. For example, while moving throughout the field, the operator of a work vehicle must be careful to avoid damaging or crushing crops. Sprayers, in particular, require a high degree of maneuverability since they must travel over crops to provide chemicals to the agricultural field.
Suspension systems, too, are integral in determining the productivity of work vehicles. One way to increase productivity in agriculture is to increase the speed of the agriculture vehicle. The necessity of low speed operation arises from inefficient design of the suspension, the parameters of which cannot be adjusted to a changing terrain, roughness of a field, or weight of the sprayer or tractor. Thus, increasing the speed of existing agricultural vehicles results in a decrease in the quality of vehicle operation and operator comfort due to increased vibration.
Another limitation of prior steering and suspension systems is that, at certain speeds, the work vehicle begins to resonate. Since the wheel width and wheel base of most work vehicles are fixed, this resonance cannot be compensated for or reduced. Therefore, the operator must slow down the speed of the work vehicle, which negatively impacts productivity.
Accordingly, what is needed is an improved steering system that has greater flexibility and is still rugged enough to handle rough, off-road terrain. In an agricultural sprayer, such a new system would allow a more efficient and direct application of products (e.g., water, fertilizer, herbicides, insecticides, etc.) to a field. Further what is needed is an improved suspension system having operator-adjustable and/or terrain-specific parameters. Further still, what is needed is an improved suspension system that would allow the operator to vary the clearance between the chassis and the ground (i.e., crop clearance).